Improbability principle

On April 23, 1999, Fernando Tatis of the St. Louis Cardinals hit agrand slam home run against Chan Ho Park of the Dodgers. That's not anoverly rare event. However, Tatis didn't hit just one grand slam offof Park. He hit TWO. And they were in the same inning. No Major Leagueplayer had ever done this before and no one has done it since. Thechances of being a witness to such a thing must be so high to make itunlikely that anyone would ever see it. And yet it happened.

David Hand's book The Improbability Principle tries to explain howsuch seemingly unlikely events not only do happen, they almost have tohappen. Hand's "principle" is actually just his way of synthesizingseveral different mathematical laws of probabilities. He does anexcellent job of explaining complicated topics in a clear and engagingmanner.

One of the most important laws to take from the book is The Law ofTruly Large Numbers. Essentially, if you give some event enoughchances to occur, it will happen. So if you think someone winning thelottery twice is impossible, it isn't. People have done it--and withbig jackpots. Why? Because there are a lot of lotteries in the world.There are so many that by chance one person will take home two bigpayouts.

There is also the Law of Near Enough. Many things that humans thinkare coincidences are just our way of drawing parallels between thingsthat are close. Say that I know the value of pi to 20 digits. You knowit to 10 digits. We both think we know the value of pi. But we don'tboth know the exact same number. But for most people it's near enough.

Hand also mentions probability levers. Certain outside influences canchange the probability of an event occurring. In the case of Tatis'two grand slams, he was playing in an era when there were many homeruns hit. He was also facing the same pitcher twice who was tiringbecause he was throwing many more pitches than normal. Both of thosefactors made the two grand slam home runs a bit more likely, albeitstill highly unusual.

Our brains are trained to look for patterns and coincidences it seems.But our brains aren't as well trained at figuring out probabilities.We go to casinos and play roulette and bet on numbers that haven'tcome up recently because "they're due." Basketball players keeppassing the ball to a teammate who may have made two shots in a rowbecause "he has a hot hand." But, these can all just be randomvariations. It just happens.

The Improbability Principle may make you think that everything israndom. Weird coincidences may seem a little less special, but you mayalso feel special knowing the reason why that is so.